DBS has come under fire from Treasury economic secretary Helen Liddell for lack of progress in the pension review.
Liddell has publicly criticised DBS for figures which show a doubling in the number of its review cases.
But DBS chairman Ken Davy says the figures for the 1,800-member network include non-priority phase two cases, which most other firms have yet to include.
The most recent Treasury figures, up to the end of February, show DBS with 2,506 cases and a clear-up rate of just 7 per cent compared with last month's 1,302 cases and 10 per cent clear-up rate.
Liddell said in the House of Commons that firms have made further progress, with about 65 per cent of cases identified for review now completed.
But she added: "The general trend hides a wide range of different performances. A few firms, eight in all, have yet to complete even half their cases. One is still some way short of the 10 per cent mark."
Davy says: "We are disappointed at the interpretation. We have been able to accelerate the process and our figures do include all our phase two cases, unlike the majority of organisations. Like is not being compared with like."
He says DBS revisited the whole review process and has identified extra cases.
DBS was hit with a £425,000 fine in September for slow progress with the review.
Countrywide, slammed by the PIA last month for submitting different figures to the regulator and the Treasury, has now completed 39 per cent of its cases.